In an electrophotographic image forming apparatus, accompanied by rotation of a photosensitive drum, an electrostatic latent image is formed on a circumferential surface of the photosensitive drum, and then, toner is supplied from a development roller onto the circumferential surface of the photosensitive drum. As a result, the electrostatic latent image is developed into a toner image. The toner image is carried by the circumferential surface of the photosensitive drum. In a downstream side of the development roller in a rotation direction of the photosensitive drum, a transfer roller is disposed facing the photosensitive drum. Accompanied by the rotation of the photosensitive drum, a sheet is supplied between the photosensitive drum and the transfer roller at a timing that the toner image carried on the circumferential surface of the photosensitive drum faces the circumferential surface of the transfer roller. Due to function of a bias applied to the transfer roller, the toner image is transferred from the circumferential surface of the photosensitive drum onto the sheet, such that image (toner image) forming on the sheet is achieved.
The image forming apparatus provides a so-called double-side mode, in which after an image is formed on one face of a sheet, faces of the sheet is reversed and conveyed such that an image is formed on another face of the sheet.
The image forming apparatus having the double-side mode includes, for example, a main conveying path for conveying the sheet through an image forming section having the photosensitive drum to an discharge port, and a sub conveying path for reversing the faces of the sheet, on which an image has been formed by the image forming section, and conveying the sheet to the image forming section.
Each roller provided in the photosensitive drum, the main conveying path, and the sub conveying path is rotated, for example, based on an output of a single reversible motor. That is, based on the output of the reversible motor performing forward rotation, the photosensitive and each roller of the main conveying path is rotated. As a result, the sheet is conveyed through the main conveying path, and the toner image from the photosensitive drum is transferred onto the sheet. Meanwhile, based on output of the reversible motor performing reverse rotation, each roller of the sub conveying path is rotated, and the sheet is conveyed through the sub conveying path. In view of restraining deterioration of the photosensitive drum, for example, a clutch is installed between the reversible motor and the photosensitive drum, so that when the reversible motor performs the reverse rotation, connection between the reversible motor and the photosensitive drum is disconnected by the clutch.